Glass syringe for injections and similar purposes



Dec. 13, 1927.,

- A. GUNTHER emss SYRINGE FOR mJsc'uons' AND snumk PURPOSES rile -n5. '11. 192'? 3% red m 1 rmmsa e 13,1921.

FFECE 7 mean eimrnna, or scnmmnarnm, GERMANY.

GLASS SYBINGE FOR INJEOTIONS AND SmIIiAR PURPOSES.

. Application filed February 11, 1e27, Serial No.'167,518, and in Germany January 12, 1927. I

This invention relates to a glass syringe for injections and other purposes in which a glass piston is fitted into a ground cylinder body on which a scale or scales are marked.

5 This glass syringe is characterized in that the hollow glass piston closed at the lower end by a flatbottom plate is made of "coloured glass and is lined on the inner surface with a mirror-foil which is silver or of I similar colour so that the mirror foil in combination' with the colour of the glass of the piston clearly indicates the position of this piston and specially that of its closed bottom end on the scale or on the scales of the cylinder body, no separate bottom plate of opaque glass of a different colour being fixed by melting on the open end of the piston. The flat bottom of the piston sits-tightly on the flat end of the tubular part of the piston body when the piston is pushed home and it closes tightly this end of the cylinder body.

In syringes for injection and similar purposes of known type and which have a measuring scale or measuring scales a glass plate of o aque glass has been fixed by melting on the ower open end of the piston designedfor making the osition of the iston in the cylinder bod visible through t e glass wall of the cylin or body, Injection syringes of this t pe present certain inconveniences. The glass bottom of the piston of opaque I glass possesses generally another expanding capabllity than the transparent glass of which the piston is made, wherefrom results that the bottom plate of opaque glass breaks easily off the piston. In this case the liquid which had been sucked into the syringe penetrates into the piston so that the glass syrin e was unfit for use.

It as been proposed to make the piston more visible through the glass wall of the cylinder body by arranging a copper mirror in the piston; the bottom was however not clearly visible so that it was necessary to fix a plate of opaque glass by melting onto the bottom end of the cylinder.

This inconvenience is avoided according to the inventionby blowing the hollow pis a ton from coloured, preferably darkish yellow glass and by fittmg it with a silver mirror or with a mirror of other colour lining the inner wall of the hollow piston.

Owing to. this silver mirror and owing to the yellow colour the piston is clearly visiblethrough the transparent glass wall of the cylinder body and the position of the piston in the cylinder body can be accurately read on the scale or scales as the silver mirror reflects metallically.

In order to avoid dead space in the syringe co the bottom of the piston is flat and also the end'of the tubular part of the cylinder so that the piston sits tightly upon the flat end pf ttlhe cy inder and closes the cylinder perec y.

An embodiment of the invention is illustrated, by way of example, in the accompanymg drawings in which Fig. 1 shows the improved injection syringe in elevation,

Fig. 2 shows the cylinder body in section and the piston in elevation.

v The syringe consists of a cylinder body 1 i of transparent glass and of a hollow piston. .2 made of coloured, preferably yellow glass re.

and lined injthe hollow space 3 with a mirror foil of silver or the like, so that the piston looks as if it were of gold. The inner edge or end canbe -consequently clearly seen through the transparent glass of the cylinso der bodyand as the glass plate 4 which"; forms the bottom of the piston is thin plane .clear glass the position of the same can be accurately ascertained. That is, there is a very distinct line 4' at the junction of the plate 4 with the end of the gold barrel of the piston, and thus this line coacts with the digits of the scale or graduations and clearly indicates the contents in the space. between the bottom 5 of the body 1 and the plate 5 of the cylinder. The bottom plate 4 of the piston is flat, while the end 5 of the tubular portion of the cylinder body is also flat so that the flat iston bottom sits closely on the flat end 5 of the cylinder bodv without any clearance and tightly closes the end of the cylinder body when the piston has been pushed I claim:

A glass syringe comprising in combinathe hollow piston so that the position wheremy hand. I by the point of demarkation between the end i tion a ground cylinder body of transparent of the colored and mirrored end-of the pisglass on which a measnring'scale is marked, ton and the Blate form a distinctive visible and a ground hollow pistonof yellow glass, index throug the body for cooperation with 1 a thin clear plate of glass sealing the end, a. the scale thereon. v silver mirror foil on the inner surface of In testimony whereofl have hereunto set- ALFRED GI'JNTHER 

